SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66740db4370fb656de40571fac2a37fd5290f4c61a0af968f70e63d8edd3d611' 
  AND token = 'Xk5gVQIfO19ZGlFIftxKBqbRbjrqppDXgTyJb9fBAzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}